Microsoft Exchange Online Service Descriptions

Microsoft Exchange Online is a hosted messaging solution that delivers the capabilities of Microsoft Exchange Server as a cloud-based service. It gives users access to email, calendar, contacts, and tasks from PCs, the web, and mobile devices. It integrates fully with Active Directory, enabling administrators to use group policies, as well as other administration tools, to manage Exchange Online features across their environment.

Organizations that subscribe to Exchange Online retain control over the messaging services they offer to users, but they do not have the operational burden of on-premises server software. With the Exchange Online hosted plans described in this document, email is hosted on servers that support multiple customers simultaneously. These servers are housed in Microsoft data centers and are accessible to users on a wide range of devices from inside a corporate network or over the internet.

To compare features across plans, see Compare Office 365 for Business plans. To compare plans for Office 365 Germany, see Office 365 Germany subscription plans.

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What’s new in Exchange Online

For information about new features in Exchange Online, see What’s New in Exchange Online.

Office 365 plans for Exchange Online

Office 365 is available in a variety of plans to best meet the needs of your organization. For information about different plans, including standalone plan options and information on moving from one plan to another, see Office 365 plan options.

Each user who accesses the Exchange Online service must be assigned to a subscription plan, and each user subscription has its own mailbox. Folders and messages in these mailboxes reside on a computer running Exchange Server at a Microsoft data center.

User subscriptions are not required for conference rooms and shared mailboxes. These special mailbox types do not have login credentials. Instead, licensed users with the appropriate permissions manage and access them via delegation.

System requirements for Exchange Online

For system requirements for Office 365, the monthly subscription-based service available for business, education, and government organizations, please see Office 365 system requirements.

Storage and recipient limits for Exchange Online

For information about the storage and recipient limits available in the Exchange Online subscription plans, see Exchange Online Limits.

Feature availability across Office 365 plans

If your organization currently has subscriptions to Office 365 Small Business, Office 365 Small Business Premium, or Office 365 Midsize Business, visit your Message Center in the Microsoft 365 admin center or talk to your Office 365 provider for more details on how the new Office 365 Business plans impact you. To learn more about the new Office 365 Business plan family, see New Office 365 plans for small and mid-sized businesses.

¹ Requires an Exchange Online Archiving subscription for each on-premises mailbox user that has a cloud-based archive.
² Azure Information Protection is not included, but it can be purchased as a separate add-on and will enable the supported Information Rights Management (IRM) features. Some Azure Information Protection features require a subscription to Office 365 ProPlus, which is not included with Office 365 Business Essentials, Office 365 Business Premium, Office 365 Enterprise E1, Office 365 Education, or Office 365 Enterprise F1.
³ Windows Server AD RMS is an on-premises server that must be purchased and managed separately to enable the supported IRM features.
⁴ Transport rules are made up of flexible criteria, which allow you to define conditions and exceptions, and actions to take based on the criteria. The available criteria and actions differ between Exchange Online, and Microsoft Exchange Server 2013. For a list of available criteria and actions, see the corresponding criteria and action topics for each product.
⁵ For Exchange 2013, DLP requires an Exchange Enterprise Client Access License (CAL). For more information about CALs and server licensing, see Exchange Server Licensing.
⁶ Exchange Server 2013 has most of the same built-in anti-spam capabilities as Exchange Server 2010. For information about the benefits of Exchange hosted spam filtering over the on-premises offerings, see Benefits of Anti-Spam Features in Exchange Online Protection Over Exchange Server 2013.
⁷ Only accessible via direct access to the Exchange admin center (EAC) management interface.
⁸ Exchange Server 2013 uses only the Microsoft anti-malware engine. Exchange Online uses multiple anti-malware engines to scan inbound, outbound, and internal messages for malware.
⁹ An EOA subscription can be purchased separately for each mailbox that requires the inactive mailbox feature.
¹⁰ SharePoint must be deployed in the on-premises Exchange organization.
¹¹ SharePoint Online must be included in the Office 365 subscription plan.
¹² POP is supported, but IMAP is not.
¹³ Supported for Exchange Server 2013 on-premises customers who purchase Azure Information Protection. Office 365 Message Encryption requires on-premises customers to route email through Exchange Online, either by using Exchange Online Protection for email filtering or by establishing hybrid mail flow.
¹⁴ Exchange Server 2013 customers need to download and install SP1 to access Document Fingerprinting and Policy Tips in OWA and OWA for Devices.
¹⁵ BitLocker Drive Encryption is supported for Exchange Server 2013, but an administrator needs to enable the feature.
¹⁶ Office 365 Business Essentials, Office 365 Business Premium, and Office 365 Enterprise F1 do not provide access rights for utilization with on-premises servers. To be compliant, the customer must purchase or have previously purchased the appropriate CALs or upgrade to an Enterprise SKU that provides these access rights.
¹⁷ Connected accounts are supported for POP & IMAP accounts but disabled for Outlook.com (Hotmail).
¹⁸ Using cmdlets in Exchange Online PowerShell to customize the default address lists and the default global address list (GAL) is not supported.
¹⁹ Some third-party web parts and add-ins may not be available.
²⁰ For eDiscovery, you need a separate query for on-premises vs. cloud.
²¹ The table indicates whether or not the client works with the associated plans. It does not mean the clients are necessarily included in the purchase of these plans.
²² For more information, see Controlling your data in Office 365 using Customer Key.
²³ Exchange Online UM support for third-party PBX systems via direct connections from customer-operated SBCs will end in April 2019. Please see the Exchange team blog Discontinuation of support for Session Border Controllers in Exchange Online Unified Messaging for more information.
²⁴ An F1 user cannot add delegates to their own mailbox, but they can access another mailbox (including shared mailboxes) and perform any actions which have been delegated to them.

Feature availability across Exchange Online standalone plans

¹ Transport rules are made up of flexible criteria, which allow you to define conditions and exceptions, and actions to take based on the criteria. The available criteria and actions differ between Exchange Online, and Microsoft Exchange Server 2013. For a list of available criteria and actions, see the corresponding criteria and action topics for each product.
² For information about the benefits of Exchange hosted spam filtering over the on-premises offerings, see Benefits of Anti-Spam Features in Exchange Online Protection Over Exchange Server 2013.
³ SharePoint must be deployed in the on-premises Exchange organization.
⁴ SharePoint Online must be included in the Office 365 subscription plan.
⁵ Requires an Exchange Online Archiving subscription for each on-premises mailbox user that has a cloud-based archive.
⁶ An Exchange Online Archiving subscription can be purchased separately for each mailbox that requires the inactive mailbox feature.
⁷ Exchange Server 2013 uses only the Microsoft anti-malware engine. Exchange Online uses multiple anti-malware engines to scan inbound, outbound, and internal messages for malware.
⁸ Only accessible via direct access to the Exchange admin center (EAC) management interface.
⁹ IMAP is not supported.
¹⁰ For Exchange 2013 or later, DLP requires an Exchange Enterprise Client Access License (CAL). For more information about CALs and server licensing, see Exchange Server Licensing.
¹¹ Azure Information Protection is not included, but it can be purchased as a separate add-on and will enable the supported Information Rights Management (IRM) features. Some Azure Information Protection features require a subscription to Office 365 ProPlus, which is not included with Office 365 Business Essentials, Office 365 Business Premium, Office 365 Enterprise E1, Office 365 Education, or Office 365 Enterprise F1. Office 365 Message Encryption depends on Azure Information Protection.
¹² Windows Server AD RMS is an on-premises server that must be purchased and managed separately to enable the supported IRM features.
¹³ Supported for customers running Exchange Server 2013 or later who purchase Azure Information Protection. Office 365 Message Encryption requires on-premises customers to route email through Exchange Online, either by using Exchange Online Protection for email filtering or by establishing hybrid mail flow.
¹⁴ Customers running Exchange Server 2013 or later need to download and install the latest cumulative update (CU), or the immediately previous CU, to access Document Fingerprinting and Policy Tips in OWA and OWA for Devices.
¹⁵ Available to customers running Exchange Server 2013 or later.
¹⁶ BitLocker Drive Encryption is supported for Exchange Server 2013, but an administrator needs to enable the feature.
¹⁷ Exchange Online Plan 1 has a size limit on the mailbox and archive. Exchange Online Archiving for Exchange Online add-on adds unlimited cloud-based archive and In-Place Hold.
¹⁸ Exchange Online Kiosk calendars can only be accessed or shared through OWA.
¹⁹ Connected accounts are supported for POP & IMAP accounts but disabled for Outlook.com (Hotmail).
²⁰ Using cmdlets in Exchange Online PowerShell to customize default address lists and the default global address list (GAL) is not supported.
²¹ Some third-party web parts and add-ins may not be available.
²² For eDiscovery, you need a separate query for on-premises vs. cloud.
²³ Exchange Online Kiosk does not provide access rights for utilization with on-premises servers. To be compliant, the customer must purchase or have previously purchased the appropriate CALs or upgrade to an Enterprise SKU that provides these access rights.
²⁴ Office 365 Groups is available with reduced functionality.